Management of Intraventricular Delay in Adults with Cardiovascular Disease

Initial Diagnostic Approach

The American Heart Association recommends precise electrocardiographic classification as the first step in managing intraventricular conduction delay, as management differs substantially by conduction pattern 1
The American College of Cardiology suggests that complete RBBB is characterized by QRS ≥120 ms with rsr′ pattern in V1/V2, S wave >40 ms in leads I and V6 1
The American Heart Association states that complete LBBB is characterized by QRS ≥120 ms with broad notched R waves in I, aVL, V5-V6, absent Q waves in I, V5-V6, and R peak time >60 ms in V5-V6 1
The American College of Cardiology recommends that nonspecific IVCD is characterized by QRS >110 ms without meeting RBBB or LBBB morphology criteria 1, 4

The American Heart Association recommends that asymptomatic patients with isolated bundle branch block and 1:1 AV conduction should not receive a permanent pacemaker (Class III: Harm) 1, 3
The American College of Cardiology suggests that permanent pacing is indicated in symptomatic patients with second-degree Mobitz type II AV block (persistent or infranodal), high-grade AV block, or third-degree AV block (persistent or infranodal) 1, 2, 4
The American Heart Association states that temporary pacing indications in acute myocardial infarction include symptomatic or hemodynamically significant bradycardia, and atropine may be used as a first-line treatment 2, 7

The American College of Cardiology recommends that cardiac resynchronization therapy (CRT) may be beneficial in patients with symptomatic heart failure (NYHA class II-IV), LVEF ≤35%, and QRS ≥120 ms with intraventricular conduction delay 7
The American Heart Association suggests that guideline-directed medical therapy for heart failure patients with IVCD should include ACE inhibitors or ARBs, beta blockers, aldosterone antagonists, and diuretics for volume management 8
The American College of Cardiology states that medications that worsen heart failure, such as most calcium channel blockers and antiarrhythmic drugs, should be avoided 8, 9

The American College of Cardiology recommends that athletes with QRS ≥140 ms should undergo echocardiography to exclude structural disease 4
The American Heart Association suggests that permanent pacing with defibrillator capability is reasonable for patients with Kearns-Sayre syndrome and any conduction disorder if meaningful survival >1 year is expected 3